Details

Date

1854

Author

Snow

Contribution

Reported epidemiological evidence of water as carrier of cholera.

Reference

Norman

Notes

John Snow. Waller points out that although Snow's conclusion was subsequently borne out, his evidence was not as strong as popular myth would have it. Association of cholera cases with drinking water from a particular (Broad Street) pump was also consistent with the theory that putrid material in the vicinity of the pump had given off miasma that had caused the illness. Snow had no direct evidence of the presence of a germ, nor did he have grounds for suggesting that cholera is in all cases associated with drinking contaminated water. [Met resistance because of expert opinion about Yellow Fever. See 1822, and McNeill p. 266.]
Steven Johnson, in The Ghost Map, Riverhead, 2006, reviews the background, significance and mythology of Snow's contribution. Snow's famous epidemiological map was produced after, not before, the meeting of the Board of Governors of St. James parish at which a decision was made to removet the handle of the Broad St. pump. The outbreak of cholera was waning by the time the handle was removed. The map and the decision to disable the pump were nevertheless of great importance. Among other things, they played a role in converting the Rev. Whitehead from an opponent to a proponent of Snow's theory. Whitehead's own investigation then played a crucial role in confirming and extending Snow's work.